To be honest it is not just Covid, Post Viral Syndrome effects a lot of people. I had a bad case of flu back in the mid 1980s, caused my gums to recede, I am getting the last of my teeth extracted tomorrow and a full set of dentures. I caught Covid over Christmas 2022. Moderate flu like symptoms for 36 hours plus complete loss of sense of smell and taste, as I was recovering, I noticed I was also having difficulty hearing family members if I was not looking directly at them. My sense of smell and taste returned slowly, but my hearing is still at the level I will need hearing aids. At the minute I am still being evaluated by the local GP surgery. Talking to people who have not recovered their full health after Covid, some who caught it as far back as Spring 2020, I suspect you only need to catch a virus once to suffer medical complications, though the more times you catch one the more opportunity for your body to have a bad reaction.